The provision and display of advertisements to users of the internet is well known. It is further known to attempt to personalise the advertisements supplied to a particular user, in general by maintaining a user profile corresponding to some characteristics of the user, and supplying advertisement information in accordance with the user profile. The user profile information may simply categorise the user in accordance with demographic terms, such as age, gender or geographical location, or may be a more detailed profile based on the user's recorded browsing habits, purchasing patterns or indeed on information voluntarily submitted by a user.
Where such profiles are maintained and stored, there are potential problems with user privacy, in that personal or private information may be made available to third parties in a manner which is not desirable to the user. This is particularly the case where the user can be personally identified by information stored in the profile and made available to third party systems.
Another issue that arises in connection with providing advertisements is where the content information requested and received by the user is not in response to, for example, a single page request generated by the user, but is broadcast content information transmitted to a number of users. Such content data may for example comprise a Digital Video Broadcasting (DVB) broadcast, internet radio, podcasts, and other visual or audio content transmitted to a plurality of users. Where such broadcast content is provided to a large number of users, any advertisement transmitted with the content will of necessity be generic and non-personalised, although the advertisements may of course be selected in accordance with the transmitted content.